To avoid rutting, the AC should be very stiff (i.e. with a high |E*| value) at high temperatures, whereas to avoid fatigue, the AC should be soft (i.e. with a low |E*|) at moderate temperatures. From a lean engineering perspective, the higher the level of distresses, the lower the value of the pavement, and the higher the waste due to premature maintenance and/or rehabilitation. On the other hand, over-designing the pavement such that no distresses are present over its service life generates waste in terms of excessive use of natural resources (aggregates and bitumen). The optimal lean pavement is one that exhibits adequate performance over its service life (i.e. limited distresses) with just enough resource consumption.